Dolores O’Riordan, the frontwoman for Irish alt-rockers the Cranberries, has pleaded guilty to assaulting three policemen and a flight attendant in an altercation that dates back to November 2014.

O’Riordan reportedly stomped on a flight attendant’s ankle as her flight from New York to Shannon, Ireland, landed in November of last year. As police escorted the singer off the plane, she spat and kicked at the officers and head-butted one. O’Riordan accepted the charges in court in Ireland on Wednesday (Dec. 16). She claims she was experiencing a psychotic episode at the time.

A judge ordered O’Riordan to write letters of apology to the flight attendant and policemen involved. She will receive a sentence early next year, which could range anywhere from a fine to six months in jail.

It’s been more than 20 years since the ‘90s alt-rockers issued their breakthrough debut Everybody Else Is Doing It, So Why Can’t We?, which boasted hit singles “Dreams” and “Linger.” They most recently dropped their sixth full-length Roses in 2012.